YRV Premium Engine dead or alive.


YRV been with a local garage for almost 2 weeks.
Originally advised that it was a heat sensor. Now advised that it could be no 1 fuel injector or the
Engine is nearing its end.

Symptom - Whilst overtaking I noticed that the car had no power to continue the maneuver. Managed to continue at 50/60 mph to a lay-by where the car sounded as if it was mis-firing when stationary. Managed to start the car twice but the juddering/mis-firing continued.

The car now has no problem starting and running when cold but when if gets hot the juddering/mis-firing returns.

Almost 2 weeks ago the Mechanic advised that too much fuel was getting to piston 1 because the coolant sensor was advising that it was cold.

Have since been advised that 1. The injectors could be faulty, so they are are now swapping 1 and 2 over. However, They also advised that the spark plugs were knackered (They fitted them last year - black in colour) and when revving at high revs there is a lot of smoke.

Any thought on the Knackered engine